Time Zones

The Sun shines on different parts of the Earth at different times. So, while someone in England is having breakfast and watching the sunrise, someone in India is having their midday meal, someone in New Zealand in the South Pacific is watching the sunset, and it is the middle of the night in the Americas.

World Time Zones Map

Below is a map of the world time zone. If you click on the map, you’ll get an enhanced version of the time zones.

Calculate Local Time, How To

The local time for a location can be calculated using the time zone for the location. The reference time for time zones was originally called Greenwich Mean Time (GMT), but is now referred to as Coordinated Universal Time (UTC).

The time for a location is given relative to UTC. Some examples:

Los Angeles, California, USA: UTC-8 (e.g. if it is 12noon UTC, then it is 4am in Los Angeles)

New York, New York, USA: UTC-5 (e.g. if it is 11am UTC, then it is 6am in New York)

Stockholm, Sweden: UTC+1 (e.g. if it is 12noon UTC, then it is 1pm in Stockholm)

Mumbai, India: UTC+5 (e.g. if it is 1pm UTC, then it is 5pm in New Dehli)

Tokyo, Japan: UTC+9 (e.g. if it is 11am UTC, then it is 8pm in Tokyo)

Where the adjustment for time zones results in a time after 12 midnight, then the date at the location is one day later. Here are some examples:

Cairo, Egypt: UTC+2 (e.g. if it is 11pm UTC on Monday 15 March, then the time in Cairo is 1 am, Tuesday 16 March)

Auckland, New Zealand: UTC+12 (e.g. if it is 9pm UTC on Wednesday 30 June, then the time in Auckland is 9 am, Thursday 1 July)

Where the adjustment for time zones results in a time before 00:00 (i.e. midnight), then the date at the location is one day earlier. More examples:

Buenos Aires, Argentina: UTC-4 (e.g. if it is 3am UTC on Saturday 23 July, then the time in Buenos Aires is 11 pm, Friday 22 July)

Honolulu, Hawaii, USA: UTC-10 (e.g. if it is 6am UTC on Monday 1 May, then the time in Honolulu is 8 pm, Sunday 30 April)

Note: The time zone adjustment for a specific location may vary due to the use of daylight saving time. * e.g. New Zealand which is usually UTC+12, observes a one hour daylight saving time adjustment during the southern hemisphere summer resulting in a local time of UTC+13!

Calculating time difference between two citys

The time difference between two locations can be determined by subtracting the UTC time adjustment of the current location from the UTC time adjustment for the target location. Some examples:

You are in Paris, France (UTC+1) and want to know the time in Shanghai, China (UTC+8).

First subtract your local UTC adjustment (+1) from the adjustment for the target location (+8) giving an adjustment of Local Time +7 (+8 – +1 = +7)

So, if it is 3pm in Paris, it will be 10pm in Shanghai.

You are in Shanghai, China (UTC+8) and want to know the time in Paris, France (UTC+1).

First subtract your local UTC adjustment (+8) from the adjustment for the target location (+1) giving an adjustment of Local Time -7 (+1 – +8 = -7)

So, if it is 11am in Shanghai, it will be 4am in Paris.

You are in New York, USA (UTC-5) and want to know the time in Rome, Italy (UTC+1).

First subtract your local UTC adjustment (-5) from the adjustment for the target location (+1) giving an adjustment of Local Time +6 (+1 – -5 = +6)

So, if it is 3pm in New York, it will be 9pm in Rome.

You are in Rome, Italy (UTC+1) and want to know the time in New York, USA (UTC-5).

First subtract your local UTC adjustment (+1) from the adjustment for the target location (-5) giving an adjustment of Local Time -6 (-5 – +1 = -6)

So, if it is 2pm in Rome, it will be 8am in New York.

Again, where the adjustment crosses midnight, then the date must be adjusted accordingly:

For instance, someone wants to make a business phone call phone call from Washington DC, USA (UTC-5) to Sydney, Australia (UTC+11). The time difference is +16 hours.

If they try to make this call at 8:30am on Thursday, the time in Sydney would be 12:30am Friday.

They would be better to wait until 5pm to make the call, when the time in Sydney would be 9am Friday.

If they waited until 8am Friday in Washington DC to make the call it might not get answered as it would be Saturday in Sydney.

This works both ways:

For instance: someone calling from Sydney to Washington DC on Monday might not get through as it would still be Sunday in Washington DC.

Adjusting for Daylight Saving Time

Daylight saving time adds one hour to the local time (UTC+1). Some examples:

Chicago, Illinois, USA, is normally UTC-6, but during the Northern Hemisphere summer it is UTC-5.

New Zealand in the South Pacific is usually UTC+12, but during the Southern Hemisphere summer it is UTC+13!

Once the daylight saving time adjustment has been made to the UTC for the location, then the calculations can be performed exactly as given above.

World Time Zones – Listed Below

Some zones north-south of each other in the mid Pacific differ by 24 hours in time: they have the same time of the day but differ by a full day. The two extreme time zones on Earth (both in the mid Pacific) differ by 26 hours. A particular day starts earlier in countries with a more positive UTC offset. Thus the first occurrence of a date will be in UTC + 14 and the last of the same date in UTC – 12 (at sea). This gives the interesting feature that during one hour each day there are three different dates in use on land around the world, at 10:30 UTC Monday it is already 00:30 Tuesday in the Line Islands (UTC + 14) while the time is 23:30 Sunday in Samoa (UTC – 11) [3].

Time zone abbreviations are almost always customary, not legal – those listed here only exist in English and are somewhat arbitrary. English time zone names below generally only apply to English-speaking areas. The CIA and NAO disagree on the time kept by some Russian oblasts, so both are given below – this may be due to a recent time zone change.

French Polynesia
Gambier Islands
United States (AKST-Alaska Standard Time)
Alaska (most of state)*

UTC – 8, U (Time Zone)

Canada (PST-Pacific Standard Time; the corresponding daylight saving time is called Pacific Daylight Time – PDT, UTC – 7)
British Columbia (most of province)*,
Yukon*
Mexico
Baja California*
Pitcairn Islands
United States (PST-Pacific Standard Time)
California*
Idaho*
north of the Salmon River (between the Oregon state border and the Idaho County/Lemhi County border), and
west of the Idaho County/Lemhi County border (between the Salmon River and the Montana state border)
Nevada (most of state, except Idaho border towns and West Wendover)*
Oregon (most of state, including southern 1/5 of Malheur County)*
Washington*

UTC – 7, T (Time Zone)

Canada (MST-Mountain Standard Time)
Alberta*,
British Columbia
northeastern (no DST)
# Most of Peace River Regional District except Fort Ware, Beatton River, Pink Mountain, Sikanni Chief, Buckinghorse River and Trutch
southeastern*
# Regional District of East Kootenay,
# Regional District of Central Kootenay east of the Kootenay River and parts east of Kootenay Lake that are south of and including Riondel (Creston doesn’t observe DST), and
# Columbia-Shuswap Regional District east of the Selkirk Mountains,
Northwest Territories*,
Nunavut*
west of 102° West, and
entire Kitikmeot Region,
Saskatchewan
Lloydminster and surrounding area* (specifically exempted from the legal prohibition of DST in Saskatchewan)
Mexico
Baja California Sur*,
Chihuahua* (adopted UTC-7 in 1998),
Nayarit* (most of state)
Sinaloa*,
Sonora
United States (MST-Mountain Standard Time)
Arizona (the Navajo Nation* does observe DST, but the Hopi Reservation, an enclave within it, does not observe DST),
Colorado*,
Idaho*
south of the Salmon River (between the Oregon state border and the Idaho County/Lemhi County border), and
east of the Idaho County/Lemhi County border (between the Salmon River and the Montana state border),
Kansas*
Greeley County,
Hamilton County,
Sherman County, and
Wallace County,
Montana*,
Nebraska (western)*,
Nevada*
Duck Valley Indian Reservation, plus the towns of Mountain City and Owyhee,
Jackpot, and
West Wendover,
New Mexico*,
North Dakota (southwestern)*,
Oklahoma
Kenton*,
Oregon
northern 4/5 of Malheur County*,
South Dakota (western)*,
Texas*
El Paso County,
Hudspeth County, and
northwestern Culberson County (Guadalupe Mountains National Park area),
Utah*,
Wyoming*

UTC – 6, S (Time Zone)

Belize
Canada (CST-Central Standard Time)
Manitoba*,
Nunavut
between 85° West and 102° West (except eastern Kitikmeot Region and western Southampton Island)*,
Ontario*
Northwestern Ontario west of 90° West (except Atikokan area, New Osnaburgh and Pickle Lake area, and Shebandowan and Upsala area), and Big Trout Lake area east of 90° West,
Saskatchewan (most of province), except
Creighton and Denare Beach area, which does observe DST (unofficially, as Saskatchewan has a law prohibiting the use of DST)
Lloydminster and surrounding area, which observes Mountain Standard Time (UTC-7) with DST by special legal exemption
Chile
Easter Island**
Costa Rica
Ecuador
Galapagos Islands
El Salvador
Guatemala
Honduras
Mexico*
all other states not already mentioned, plus
Distrito Federal
Nayarit
some of Nuevo Vallarta
Nicaragua*
United States (CST-Central Standard Time)
Alabama (most of state)*,
Arkansas*,
Florida
west of the Apalachicola River, except for the portions of Franklin County and Gulf County south of the Intracoastal Waterway*,
Illinois*,
Indiana*
northwestern
# Jasper County,
# Lake County,
# LaPorte County,
# Newton County, and
# Porter County,
southwestern
# Gibson County,
# Posey County,
# Spencer County,
# Vanderburgh County, and
# Warrick County,
Iowa*,
Kansas (most of state)*,
Kentucky (western)*,
Louisiana*,
Michigan*
Dickinson County,
Gogebic County,
Iron County, and
Menominee County,
Minnesota*,
Mississippi*,
Missouri*,
Nebraska (central and eastern)*,
North Dakota (most of state)*,
Oklahoma (most of state)*,
South Dakota (eastern)*,
Tennessee*
Middle Tennessee,
West Tennessee, and
Marion County
Texas (most of state)*,
Wisconsin*

UTC – 5, R (Time Zone)

Bahamas*
Brazil
Acre,
Amazonas (southwestern)
Canada (EST-Eastern Standard Time)
Nunavut
east of 85° West*, and
entire Southampton Island (no DST),
Ontario
east of 90° West (except Big Trout Lake area)*, plus
Atikokan area (no DST),
New Osnaburgh and Pickle Lake area (no DST), and
Shebandowan and Upsala area* west of 90° West,
GTA ; Ottawa.
Quebec (most of province)*
Cayman Islands
Colombia
Cuba*
Ecuador
Haiti*
Jamaica
Panama
Peru
Turks and Caicos Islands*
United States (EST-Eastern Standard Time)
Alabama
Phenix City*,
Connecticut*,
Delaware*,
District of Columbia*,
Florida
east of the Apalachicola River, plus the portions of Franklin County and Gulf County south of the Intracoastal Waterway, west of the Apalachicola River*,
Georgia*,
Indiana (most of state), except
Clark County,
Dearborn County,
Floyd County,
Harrison County, and
Ohio County, which do unofficially observe DST,
Kentucky (eastern)*,
Maine*,
Maryland*,
Massachusetts*,
Michigan (most of state)*,
New Hampshire*,
New Jersey*,
New York*,
North Carolina*,
Ohio*,
Pennsylvania*,
Rhode Island*,
South Carolina*,
Tennessee*
East Tennessee, except Marion County
Vermont*,
Virginia*,
West Virginia*

Nepal’s time zone of UTC + 5:45 was adopted in 1986 [5]. This is the nearest quarter-hour from Greenwich to the local mean time of Nepal’s capital Kathmandu, which is at 85°19’E or 5:41:16. Old CIA maps, 1995 and earlier, have Nepal at 5:40, which may be their approximation of Kathmandu’s local mean time. See Nepal Time.

Australia (AWST-Australian Western Standard Time)
Western Australia (most of state)
Brunei
China, including the People’s Republic of China, the Republic of China (Taiwan), Hong Kong and Macau

Note that the whole of China has the same time, which makes this time zone exceptionally wide. In the extreme west of China the sun is at its highest at 15:00, in the extreme east at 11:00. It also means that on the short (76 km) frontier with Afghanistan, the official time change is 3 hours and 30 minutes. The two western autonomous regions of China, Xinjiang and Tibet, were in UTC+6 during the Republic era (1912-1949), but were moved to UTC+8 after the founding of the People’s Republic of China in 1949. Today, residents of the two autonomous regions do everything 2 hours late. For example, lunch is at 14:00 and business hour ends around 19:00.

Kwajalein, Eniwetok, and Bikini atolls in the Marshall Islands used to be on UTC-12. Kwajalein advanced 24 hours to the eastern hemisphere side of the International Date Line by skipping 21 August 1993. Eniwetok and Bikini probably advanced even earlier, when the U.S. military relinquished its control of them. [6]